Abstract: Objective To explore the effectiveness and safety of oral zomitriptan in the prodromal stage of patients with episodic cluster headache(eCH).Methods A total of 23 patients with definite prodromal stage during cluster period were selected. Their baseline headache attack data were collected, while zomitriptan was orally administered within 15 min of the prodromal stage for consecutive three attacks. Their headache characteristics at baseline and after treatment were compared to evaluate the severity and duration of headache after oral zomitryptan treatment in the prodromal phase.Results The median of maximum visual analog scale score(VASmax) of the 23 eCH patients was 9, while the median of VASmax after three times of treatment in the prodromal phase were all 5. The VASmax after treatment in the prodromal phase was significantly lower than that of baseline(P<0.01). The baseline headache duration was(75.7±38.1) min. After three times of treatment in the prodromal phase, the duration of headache was(48.2±24.5) min,(45.7±21.8) min and(52.6±31.9) min, respectively, which was significantly shorter than the baseline(P<0.01). The proportion of mild pain or painless 30 min after treatment in the prodromal phase was 13/23(56%), 16/23(70%) and 14/23(61%), respectively, and there was no statistical difference among three times of treatment. Furthermore, the incidence of adverse reactions after taking zolmitriptan was 10.1%, including light-headedness, neck stiffness, sleepiness and mild chest tightness. The degree of adverse reactions was mild.Conclusions Oral administration of zolmitriptan in the prodromal period can remarkably shorten the duration of cluster headache, and reduce the severity of headache, with a consistent effectiveness in the prodromal phase to some extent, and good safety.